Rent with an option favors the seller - it is not something I would advise anyone to do.
You could loss the deposit that will be required if you do not, or cannot buy the home.
So - if you are weak fincnacially and cannot qualify for a loan NOW, be sure you will at the end of the lease term, or any upfront/deposit money will be forfeited.
You may be asked to pay an amount of rent over and above the fair market rent - only that overage would be applied to the purchse price (NOT your entire rent) - you would lose that, too, if you do not exercise your option to buy the home.
Your choice of homes will be limited as most sellers who want to sell, and can sell, sell now, not later.
The purchase price is decided at the beginning of the lease - not at the end.
There are a number of pitfalls in this kind of arrangement............so - please make sure you fully understand what is involved before proceeding.